Edwaed weston



(No Model.)

E.- WESTON.

AMPERE METER. v No. 348,648. Patented Sept. 7, 1886.

Fig 2.

' 4 Iii UNITED STATES I PATENT OFFICE.

EDYVARD \VESTON, OF NEWARK, NEIV JERSEY, ASSIGNOR TO THE UNITED STATES ELECTRIC LIGHTING COMPANY, OF NEIV YORK, N. Y.

AMPERE-METER.

SPECIFICATION forming part of Letters Patent No. 348,648, dated September 7, 1886.

Application filed February 1, 1886. Serial No. 190,440. (No modeLl To all whom it may concern.- consists, in one formof instrument, of a broad Be it known that I, EDWARD IVEsToN, a and thick copper band, and in the simplest subject of the Queen of Great Britain, and a form of instrument the needle is placed in resident of Newark, in thecounty of Essex and front of the band, about midway between its 5 5 State of New Jersey,have inventedcertain new edges. The passage of a current through the and usefulImprovements in Ampere-Meters, copper band causes the needle to assume apoof which the l'ollowingis a specification, refcrsition the nearer the vertical as the current ence being had to the drawings accompanying increases in volume, but the increments of deand forming a part of the same. fleetion are not proportional to increments of 1 My invention is an improvement in devices current, so that, while through a certain range, known as "current-indicators or amperethe movement is ample for variations in curmeters,and whiclnby reason ofthe special use rent over a given amount, any change in curto which Iapplyit, Iterma"lamp-indicator. rent will produce a proportionately slight The apparatus is one which is to be included movement of the needle.. In order to coun- 1 in the circuit of a dynamo-electric machine teract this I attach to the back of the copper for the purpose of showing the amount of curband a soft-iron plate, with its center coincidrent which such machine is furnishing. For ing with the axis of the needle. This plate example,when several machines are connected becomes magnetized by the current flowin multiple are, one of theseindicators is used ing in the band, and exerts an attraction 20 with each machine, in order that it may be upon the magnetic needle, causing it to apseen at a glance if each machine is furnishing proximate to a vertical position. Two forces its proper amount of current. So, also,when thus coact upon the needle when current employed on any circuit containing incandesis flowing in the band, and they may be so cent lampsin multiplearc, it will show whethproportioned that nearly equal increments er all the lamps are in circuit or some turned of deflection are produced by corresponding off. In devices used for these purposes it is increments of current through a very wide manifestly desirable that any material change range. In practice I bend the copper band in the condition of the circuit should be made back upon itself, and support the needle beapparent at a glance, and that the indicatingtween the two ends or sides. I also attach a 3 o instrument should have a wide range of movesoft-iron plate to the band on each side of the ment,in order thatagiven changeintheamount needle, increasing by this means the eificiency of current shall produce a suili'ciently great of the apparatus. So far as the principle is movement or deflection of the index or needle concerned, it is obvious that, in lieu of asingle to be at once apparent. I have devised an apconductor or band, a number of insulated con- 3 paratus for doing this, the principle of its conduetors may be used, and so in many other struction and mode of operation being as folrespects the details of construction may he follows: If a magnetized needle or bar beheld greatly changed or modified without departure parallel to a conductor and a current be passed from the invention. through the said conductor, the needle or bar Ihavcillustratedin the accompanying draw- 9Q 40 tends to assume a position at right angles to ings the preferred form in which my invention the conductor or current. This principle is is or may be carried into effect. utilized in numberless instruments, the bar or Figure l is a view of the instrument in secneedle being usually held in its normal position on a line, :6 00, Fig. 2, which latter figure l tion parallel with the conductor by some diis a cross-section on line 3 y of Fig. 1. l 4 5 rective force, such as by magnetism, gravity, A is the inclosing box or case, of any desired or the force of a spring. In my said device, construction and material.

this principle of action is present. The mag- Bis a block,of copper or other metal,secured netized bar or needle is held bya pendulum in to the rear wall of the box or case. a plane parallel to a conductor or the direc- G is the copper band through which the [0o 50 tion of the current, and it carries a pointer, current passes. Its width is generally onewhich sweeps over a scale. The conductor third of its total length or slightly less. This 2 seams;

' band is bent back upon itself, as shown, and

u perforation in the band.

its ends are held by a bolt, D, that passes through a metal block, E, which is held by it in contact with the band, and a plate of insulating material, F, placed between the two ends of the band. The two blocks B and E form the terminals of the apparatus, and sockets a a,with binding-screws b,are provided in the blocks for attaching the line wire or wires to them.

Between the two sides of the band C is mounted a magnetic needle or bar, G, by pivoting-screws c, that are held in small plates d, secured to the band C, and extend through the The bar G is made of the hardest glass steel and is magnetized. From its fulcrum or spindle depends an arm, II, at right angles to it and rigidly connected, so as to serve as a counterbalance to maintain the bar in a horizontal position. The spindle also carries a light pointer, K, that is arranged to sweep over a scale, L. \Vhen a current is passed through the band C the needle is tilted more or less toward a vertical position, according to the strength of the current; but as it leaves its horizontal or normal position the increments of deflection for given increments of current become less and less.'

To remedy thisand to give greater amplitude to the deflections, I apply to the band C, on one or both sides of the needle,soft-iron plates M N. These are secured to the band in any convenient way and have perforations 02 to make room for the pivotal screws of the mag netized bar.

The iron plates serve a double purpose. They are magnetized to a certain extent by the current in the band 0, their polarity being such as to co-operate with the current in deflecting the magnetized bar toward a vertical position. On the other hand, they serve as a magnetic guard or shield to insulate and protect the needle from all extraneous magnetic influences. lVith this arrangement of parts it will be observed that the greater the deflection of the needle by the current the greater the influence upon it of the magnetic poles, and that in consequence the amplitude of the deflections produced by variations in a very strong current may be as great as that of those which take place while the needle is near the horizontal position. The device may be easily proportioned to give very exact results.

The particular construction of the device may be very greatly varied. I have shown the most eflicient'form of which I am aware; but it is obvious that similar results may be obtained by dispensing with one of the iron plates, or by placing the band C on one side only of the needle, or by using a coil or group of wires in place of the single conductingband, or by various other arrangements which are obvious modifications of that particularly shown and described.

WVhat I claim is 1. In a currentindicator, the combination,

with a conductor, of an indicating magnetized needle or bar mounted in a position parallel to said conductor, and one or more pieces of the bar or needle is deflected by the combined action of a current passing in the conductor and the magnetism induced in the iron by such current, substantially as set forth.

2. The combination, with a conductor turned or bent back upon itself, an indicating magnetic bar or needle mounted between the turns or convolutions of the conductor and parallel therewith, and one or more soft-iron pieces or plates in proximity to the conductor and the needle, these parts being so arranged that the bar or needle is deflected by the combined action of a current passing in the conductor and the magnetism induced in the iron by such current, substantially as set forth.

3. The combination, with a metal band or strip bent back upon itself, of a magnetic bar or-needle mounted between the ends or sides of the band, and parallel therewith, an indexarm attached to or moved by the needle, and iron plates secured to the band on opposite sides of the needle, as and for the purpose set forth.

4. The combination, with a metal band or strip bent back upon itself, of a magnetic bar or needle mounted between the ends or sides of the band, a weighted arm or pendulum for maintaining the needle in a normally-horizontal position and parallel with the band, an in dex-arm attached to or moved by the needle, and iron plates secured to the band on opposite sides of the needle, as and for the purpose set forth.

5. The combination, with a U-shaped conducting band or strip, of a balanced magnetic bar or needle between the ends or sides of the same, and carrying a pointer adapted to sweep over a scale, the said needle being held in a position normally parallel to the conducting band, and iron plates secured to the band on opposite sides of the needle, as and for the purpose set forth.

6. The combination, with a band or strip of copper with its ends bent back upon themselves and secured to terminal blocks or plates,

of a magnetic bar or needle mounted between the ends of the band, a counter-balance for maintaining the needle in a horizontal position parallel with the band, a pointer carried by the needle, and soft-iron plates secured to the bands on opposite sides of the needle, as herein set forth.

7. In a current-indicator, the combination of a conductor and a magnetized bar or me dle arranged to be deflected by currents passing in said conductor, and one or more magnets placed in such position relatively to the bar or needle as to co-operate with the current in deflecting the said bar, as set forth.

Witnesses: EDXVARD WESTON.

HENRY A. BEOKMEYER, J OHN O. YOUNG. 

